Two A list mild n Laixl Snails. 223 



The Reproductive System. 



The reproductive systems of tlie two species are very similai-. In 

 /'. atrainentarin, the heiinaphrodite gland is, comparatively speak- 

 ing, less compact, the hermaphrodite duct is sliorter, the all)unien 

 gland is larger and coarser, and the receptaculum seminis is slightly 

 smaller than in F. conipacta; also the vas deferens, in P. ntranien- 

 taria, i-uns a little further behind the anterior end of the penis, 

 before turning to run to its posterior end. With these differences 

 the following description applies to either species. The hermaphro- 

 dite gland haiH the form of a loose rosette, the lobes of the rosette 

 being somewhat pear-shaped. It is embedded in the liver near 

 the inner edge of "the second last whorl of the visceral hump, the 

 first whorl being that nearest the centre. From the hermaphrodite 

 gland the hermaphi'odite duct runs in a sinuous course to the 

 albumen gland. 



The albumen gland is large and compact; it is indefinitely 

 maikcd off by slight constrictions into three large and one smaller 

 lube. It lies near the beginning of the rectum, between this and 

 the first part of the intestine. The common duct is broad and about 

 half as long again as the albumen gland. One side of it is trans- 

 versely grooved, the other smooth. These two parts eventually 

 separate to form the viaduct and vas deferens respectively. 



Shortly after the division of the common duct into vas deferens 

 and oviduct, a long diverticulum is given off from the dorsal sur- 

 face of the oviduct; this ends in a little swollen knob, the recepta- 

 culum seminis. This diverticidum runs right back so that the re- 

 ceptacidum seminis is situated under the aui'icle. 



The penis is a very muscular body, lying l)eiieath the right 

 superior tentacle and across the pharynx. 



The retractor penis muscle is attached to its posterior eii<l. 



The vas deferens at first sight appears to open into the penis 

 near its anterior end. but further dissection shoAvs that it runs a 

 little liehind the anterior end of the penis, then turns and runs 

 l)ack to open into it near its ])osterior end, just near to where the 

 retiactoi- muscle is attached, at the swollen portion. Its course 

 mav be underst(K»d by refeience to Plates XVI. and XVll., Figs. 

 YI. and X. The oviduct opens to tlie exterior, just to the right of 

 the penis, through tlie genital aperture. 



The Alimentary System. 



The motith, situated on the under surface of the head, opens into 

 a relatively luige buccal mass or pharynx, running almo.st the 

 length of the foot. The walls of this pharynx are extremely mus- 



